As this sort of chromatograph sampler, as disclosed in Patent Literature 1, there is one having a mechanism adapted to introduce a constant volume of sample gas into a column.
A specific example of such a chromatograph sampler will be described with reference to FIGS. 1 and 2. This sort of conventional sampler 100 is one including: a constant volume tube 1 having an internal space of constant volume; and a fluid circuit provided on the periphery of the constant volume tube 1, and configured to, after filling a sample gas in the constant volume tube 1, switch the configuration of the fluid circuit, and send out the sample gas filled in the constant volume tube 1 to a column C.
The constant volume tube 1 is a narrow tubular-shaped one having the internal space of constant volume, and formed with a pair of fluid inlet/outlet ports 1a for introducing/leading-out the sample gas.
The fluid circuit includes a carrier introduction line 2, sample introduction line 3, sample discharge line 4, column communicating line 5, and multiport valve 6.
The carrier introduction line 2 is one into which a carrier gas (a gas not reacting with the sample gas and having a peak different from that of the sample gas, such as He, Ar, or N2) is introduced, and the start point thereof is connected to a carrier introduction port 2p communicatively connecting to an unillustrated carrier gas supply source such as a gas cylinder.
In the carrier introduction line 2, a flow rate control device 21 (hereinafter also referred to as a carrier flow rate control device 21) is provided, and it is configured to allow the flow rate of the carrier gas flowing through the carrier introduction line 2 to be controlled constant.
The sample introduction line 3 is one into which the sample gas as a measurement target is introduced, and the start point thereof is connected to a supply port 3p communicatively connecting to an unillustrated sample supply source. The sample supply source is at positive pressure higher than a reference pressure (e.g., atmospheric pressure), but the pressure is not necessarily constant. In the sample introduction line 3, a flow rate limiting member 31 formed of a throttle or a capillary is provided to limit the inflow amount of the sample gas. In addition, as the flow rate limiting member, a flow rate control device may be used.
The sample discharge line 4 is one of which the end point is connected to a discharge port 4p communicatively connecting to an unillustrated discharge space to discharge the sample fluid to the discharge space. The discharge space is kept at a constant pressure (e.g., atmospheric pressure) lower than that of the sample supply source.
The column communicating line 5 is one of which the end point is connected to the column C to send out a fluid flowing therethrough to the column C.
The multiport valve 6 has multiple ports (six here), and is configured to be able to selectively switch the connection mode among the respective ports to any of two modes.
As illustrated in FIGS. 1 and 2, each of the ports is connected with any of the respective inlet/outlet ports 1a of the constant volume tube 1, the end point of the sample introduction line 3, the start point of the sample discharge line 4, the end point of the carrier introduction line 2, and the start point of the column communicating line 5.
Also, it is configured to, when switching the multiport valve 6 to the first mode, as illustrated in FIG. 1, connect one of the fluid inlet/outlet ports 1a of the constant volume tube 1 to the end point of the sample introduction line 3, and connect the other fluid inlet/outlet port 1a of the constant volume tube 1 to the sample discharge line 4.
On the other hand, it is also configured to, when switching the multiport valve 6 to the second mode, as illustrated in FIG. 2, connect the other fluid inlet/outlet port 1a of the constant volume tube 1 to the end point of the carrier introduction line 2, and connect the one fluid inlet/outlet port 1a of the constant volume tube 1 to the column C.
When the sample gas is sent out to the column C for analysis measurement, the multiport valve 6 is kept in the first mode for a predetermined time, then after filling a constant volume of the sample gas in the constant volume tube 1, the multiport valve 6 is switched to the second mode, and the sample fluid in the constant volume tube 1 is pushed out by the carrier fluid controlled to have a constant flow rate and sent out to the column C.